The present invention relates to an internal combustion engine having at least one exhaust valve for the withdrawal of exhaust gas from at least one combustion chamber. The internal combustion engine also includes an engine brake device that is provided with a hydraulic valve auxiliary control unit that is integrated into a connection mechanism for connection of the exhaust valve with a rocker arm. The internal combustion engine is connected to an oil circuit for the supply of oil. By means of the valve auxiliary control unit, when the engine brake device is actuated the exhaust valve is adapted to be held in a temporarily open position.
Internal combustion engines of this general type are described, for example, in EP 0 736 672 B1 and EP 1 526 257 A2. The engine brake devices of these known internal combustion engines are respectively a hybrid type composed of an engine air brake and a decompression brake, which in particular are also designated as EVB (Exhaust Valve Brake). The hydraulic valve auxiliary control unit, with the variant pursuant to EP 0 736 672 B1, is installed in a rocker arm of the connection mechanism, and with the variant pursuant to EP 1 526 257 A2, is installed on one side in a valve bridge of the connection mechanism that actuates two exhaust valves at the same time. The supply of oil to the hydraulic valve auxiliary control unit is effected by means of the readily available oil circuit of the respective internal combustion engine. With both variants, in order to compensate for the play of the exhaust valve separate set screws are provided, with the aid of which the valve play adjustment can be undertaken during engine assembly and thereafter during regular service intervals. This is expensive. If the valve play is inadvertently set too great by the assembly or service personnel, chattering can occur between the rocker arm and the valve bridge, and the danger of damage to the valve drive exists. In addition, the exhaust valve does not open sufficiently, so that a complete exchange of gas cannot be ensured. If the valve play is set too small, there is the danger that in the hot state the valves do not close completely and hence burn out.
It is therefore an object of the present invention to provide an internal combustion engine of the aforementioned general type that enables a reliable and dependable operation while having an assembly and service cost that is as low as possible.